Many exercise devices have been developed in the prior art that enable a user to exercise by applying a force in reaction to a resistive force produced by the device. In one type of device, the resistive force acts only in one direction. The disadvantage of this is that the user can only exert a force in one direction against the resistive force and hence, only a single set of muscles can be exercised at any one time. Such devices are however, relatively simple. In this regard, U.S. Pat. No. 2,022,002 discloses an exercise device that essentially consists of a spring to provide the resistance. The user places the device between, for instance, his or her knees and inwardly moves the knees, towards one another, to compress the spring. As is apparent, the muscles that would be used to move the knees in the opposite direction are not capable of being exercised by this device. U.S. Pat. No. 3,659,846 provides a spring, that, at one end, is attached to an immovable object and that, at the other end, is connected to a strap worn on the knee. During an exercise routine using this device, only the muscles used for moving the knee away from the immovable object are capable of being exercised. Similarly, U.S. Pat. No. 4,022,463 discloses an exercise device that has a pair of centrally pivoted arms in which each of the arms are connected, at one end, to a spring. The user exercises by pushing the other, unconnected ends of the arms together. Again, the muscles of the user that would operate to pull the arms of the device away from one another are not capable of being exercised by the device. A more complex device is disclosed in U.S. Pat. No. 4,376,533 in which the user can push against a pair of elongated, telescopic members containing a spring or pull the ends of a rope that are attached by pulleys to the ends of the members. As is apparent from the device, the user cannot alternately push and pull the device in that the ends of the device have to be grasped in order for the user to push against the device or alternately, the rope has to be grasped in order for the user to exert a pull against the device.
As can be appreciated from the above discussion, an exercise device that is operable to offer a resistance to either a compressive or a tensile force, is, by necessity, more complex and hence, more expensive than a device that simply supplies a resistance to either a compressive or a tensile force. For instance, U.S. Pat. No. 4,376,533 discussed above, provides spring loaded telescopic members and ropes attached by pulleys to the members to provide resistances to both tensile and compressive forces. This device is to be compared with U.S. Pat. No. 2,022,002 which simply supplies a resistance to a compressive force and which essentially consists of a spring.
A device that is capable of alternately offering resistances to alternatively applied tensile and compressive forces can be even more complex than the devices discussed above. Such a device is disclosed in U.S. Pat. No. 3,971,255. The device disclosed by this patent has a shaft that axially extends through a housing. A pair of springs, located in this housing, are alternately compressed, as the user pushes and pulls the shaft through the housing. In order for the user to exert a force by his or her knees against the device, the user must be in a sitting position and a set of yokes must be fitted to the device at the shaft and at the housing. In order for the user to exert a force by his or her hands, a set of handles must be fitted to the device.
The exercise device of the present invention can offer alternate resistance to compressive and tensile forces applied to the device, to thereby alternately exercise different sets of muscles at the same time that the device is being used. The device includes, in a preferred embodiment, a deformable, resilient compression member that has a pair of opposed, spaced bearing surfaces and a pair of strap members that loop over the bearing surfaces. The strap members are connected to one another by a pair of elastic, elongated tension members. The user inserts a pair of his or her limbs into the strap members and against the bearing surfaces and thereafter, exercises by alternately exerting compressive forces on the bearing surfaces and tensile forces on the tension members through the strap members.
The compression member can essentially consist of a block of foam rubber and the tension members can essentially consist of elastomeric strips. As a result, the exercise device of the present invention can be simply and inexpensively assembled from inexpensive materials. Moreover, the simplicity of an exercise device of the present invention provides advantages that are not found in the prior art exercise devices, discussed above. For instance, the user can exert compressive and tensile forces by any combination of limbs of his or her body, thus doing away with the need for any special attachments for the device. Since strap members allow the device to be worn on the body, the user can exercise in any conceivable position. Additionally, the user can exercise at any desired pace. For instance, if a user were exercising with the device of U.S. Pat. 2,022,002, between his or her legs and the user briefly relaxed between exertions, the device would simply drop from the knees. In the exercise device of the present invention, if the user relaxes, the strap holds the device in position and on the limbs of the user.